1. Field of the Invention
This invention relates in general to traction and hydraulic elevator systems with distributed control circuits, and more particularly, to a method and control system for protecting against an excessively restrictive block operation elevator service because of the loss of communication control in the system.
2. Description of the Prior Art
The failure of communication with the hallway fixtures by a controller used with present day elevator control apparatus normally has a back-up mode of through trip or block operation with some form of service being retained, but it is of significantly inferior quality to the normal service since the building is not totally served if all car controllers are implementing a fixed block operational service to the bottom floor.
Computers have heretofore been pre-programmed to perform various functions in the operational control or management of car and hall call response strategies in an elevator system such as in U.S. Pat. No. 4,511,017 which provides emergency back-up elevator service, or a variation in block operation, when normal service is degraded, by preassigning and revising blocks of car assignments to floors in a rotational manner.
Various arrangements for elevator bank configurations have been known to benefit from the state-of-the-art solid-state controllers, but assuming that dynamically defined tasks involve progressively activated block operational failure mode arrangements; these have yet to emerge to be the least restrictive, while providing total service to the building.
With the introduction of microprocessor based elevator controllers and the distribution of electronic circuits located with each car and proximate to the respective floors, communication with the remote controllers is of fundamental concern since the integrity of hall call signals, and the control strategy in assigning cars to answer these calls, is critical to operational efficiency and to the satisfied customer. Not less important to this goal is that passengers should continue to be provided with total service in the building, with the controllers providing their most efficient service even when relegated to operate in the mode of block operation.
One of the principal problems is in providing a shared service to a floor by all of the controllers on block operation so that each associated car will service all of the floors accessible to it. All cars going on a mode of block operation which is non-adaptive does not provide the best car efficiency for the bank of cars which still has the potential for providing more efficient service to minimize waiting time.